Question

In a secure communication model, if an attacker intercepts a message and replaces it with a fake one before forwarding it, this attack is best classified as :

• A. Replay attack
• B. Masquerade attack
• C. Man in the middle
• D. Denial of service

Hint:

Intercept + Modify + Forward = MITM. It's the most dangerous "active" eavesdropping because the victims often don't know their conversation is being forged.

Answer 1

The Correct Option is C

This scenario describes a classic active attack where the adversary sits between two communicating parties. 1. Defining the Man-in-the-Middle (MITM) Attack: In an MITM attack, the attacker secretly relays and possibly alters the communication between two parties who believe they are directly communicating with each other. The specific action of "intercepting, replacing with a fake, and forwarding" is the hallmark of this attack. 2. Distinguishing from Other Attacks:
• Replay Attack: The attacker captures a valid session/message and sends it again later without changing it.
• Masquerade Attack: One entity pretends to be a different entity (often the first step of an MITM).
• Denial of Service (DoS): The goal is to make a service unavailable, not necessarily to forge messages. 3. Conclusion: Because the attacker is actively modifying the data in transit between two parties, "Man in the middle" is the most comprehensive classification for this behavior.